Vaccines: training our defenders
How a vaccine shows your body's defenders what a germ looks like, so they are ready, and how it helps protect other people too. With a lock-and-key matching experiment.
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Some germs can make us ill. Your body has a team of defenders, called the immune system, that fights them.[1][3]
A vaccine is like a practice for your defenders. It shows them what a germ looks like, without making you ill with that germ.[2][3]
Your body then makes antibodies. They help catch that one kind of germ.[3][1]
Your body remembers. If the real germ comes along later, your defenders can fight it faster and harder.[2]
After a vaccine, your arm may be a bit red and sore for 2 or 3 days, or you may feel a bit hot or unwell for a day or two. That is common and goes away.[3]
When lots of people have vaccines, germs find it hard to spread. That helps protect people who cannot have some vaccines, like very young babies.[2][7]
Long ago, an illness called smallpox made many people very ill. Thanks to vaccines, it is gone from the world.[6]
Try it: Which key fits the germ?
You need
- Card 'germs' with different shaped notches (a triangle, a square, a half-circle, a zigzag)
- Card 'antibodies' with matching shapes, plus some that do not fit
- A tray or envelope for the antibody cards
- A sand timer or stopwatch
Safety
Use cards that are already cut out, or round-ended scissors with an adult. This is a pretend game: nobody needs to talk about their own vaccines or health.
What to do
- Look at the germ cards. Each germ has a different shape on its edge.
- Mix up the antibody cards on the tray. Your teacher shows you one germ.
- Find the antibody whose shape fits that germ exactly, like a key in a lock. Time how long it takes.
- Now put that antibody to one side: your body has 'remembered' it.
- Your teacher shows the same germ again. Use the remembered antibody. Was it faster the second time?
What happens, and why?
Each antibody fits one kind of germ, like a key fits one lock. The first time, your body has to find the right one, which takes time. A vaccine lets your body find it in practice, and your body remembers it, so the next time the real germ comes the defence is much faster.[4][2]
Play: True or not true?
Read each card about vaccines. Is it true or not true? Pick the right box.
Your best score is kept only on this device. Nothing is sent anywhere.
Quiz
Other ages: Ages 10–11 · Ages 15–16